Speed-reducing gear arrangement for steam-turbines.



.Y. OGAWA. SPEED REDUCING GEARARRANGEMENT FOR STEAM TURBIN ES.

APPLICATION FILED JAN. II, 1917.

l Patented Jan; 15, 1918.?

' Yeiiarq Ogawq corresponding change in the torsion. and

UNITED STATES PATENT OFFICE.

'YEITARO OGAWA, OF KUSUNOKI MACHI. K BE, JAPAN.

srnnn-nnnucme GEAR ARRANGEMENT ron simian-renames.

To all whom it may concern:

5 pan, have invented new and useful Improvements in Speed-Reducing Gear Arrangements for Steam-Turbines, of which the following is a specification.

This invention relates to speedreducing gear arrangement for steam turbines, where in a pair of steam turbines rotating at the same speed are fixed to a. common main shaft, and a driving pinion is mounted on said main shaft between the said turbines in such a way that the said driving pinion shall gear with a driven wheel either d1- rectl or tln-ough intermediate shaft, so that the riving pinion may receive an equal re volving force from both sides. The ob ect of this invention is to reduce the torsion and bending of the main shaft and to make such torsion and bending equalon both sldes of the driving pinion whatever the load or speed may be, in order that the driving pinion might always gear with the driven "wheel exactly without being affected by the said torsion or bending and that the pressure on the teeth might be uniformly'distributedalong the whole width of the. teeth.

Figure 1 is a plan of this invention, while 5 diagrammatically show a, few applications of the invention to turbine ar- I rangemena In all the figures the same or corresponding parts are referred to with the same numbers.

As may be seen from Fig. 1, this invention {has two steam turbines 1 and 2 rotating at I the same'speed on a common shaft 3. On

this shaft between the said turbines, a driving pinion. 4 is mounted, and the driving pinion gears with a driven wheel 5, which drives. a propeller or any other driven shaft 6. \Vhen desired, the main shaft 3 may be fitted with clutches 7 by which it can be con- 4'5 nected to or disconnected from the shaft 3 of the driving pinion 4.

The speed-reducinggearing hitherto in use has only one steam turbine, and the driving pinion is mounted at one end of its shaft. But inasmuch as the driving pimon is driven from one side only, the. power transmitted to the driven wheel is generally very great. Moreover, the main shaft being of comparatively a small diameter, any change in the load or the speed produces Specification of Letters Patent.

Patented J an. 15,1918.

Application filed January 11, 1917. Serial No. 141,791.

bending thereof. The driving pinion thus influenced cannot always ear .Wltll .the driven Wheel exactly, an pinions and toothed wheels having generally broad but fine and delicate teeth, the pressure between the teeth caused by thepower transmitted is not, evenly brought to bear on the entire surface of the teeth. The result is partial wearing of the teeth, and' consequently greater friction and less efiiciency, and some times breaking of the wheels due to the shock produced on-the teeth. The above has always been one of the Worst difficulties one had to meet with in the steam turbine gearing, and a common method adopted to obtain exact gearing has been to provide a fine clearance between the teeth and to construct a special bearing of a complicated nature. In my invention however the driving pinion, as has been stated, is placed be tween two turbines rotating at thesame speed and'receives equal driving force from both sides. Consequently not only are the torsion and bending of the main shaft reduced but they are always equal "on both sides whatever the load or the speed of roi I I tation may be. Consequently the driving pinion is notatfected by them 'in the least, y

but revolves eractl' about the true axis, the

gearing of the rivi ng pinion .with the driven wheel remains always unchanged, and the. pressure on the teeth is distributed uniformly over the whole width of teeth.

'With' myinvent'ion, therefore, neither the special shaft bearing nor the clearance between teeth are necessary, and as the teeth do not wear, the efiiciency of the turbines is very high.

Since this invention consists, as we have seen, in moving the driving pinion by two turbines placed on either side thereof, it can be applied to various kinds of-turbme ar rangement, and Figs. 2 to 5 show some examples of its applications. In F igL2, two turbines 1 and 2 receive steam simultaneously through pipes 8 and exhaust it into a. condenser or low pressure turbines or engines through pipes 9. Fig. 3 shows a set of compound type in which the steam first enters the highpressure turbine 1 through.

pipe 8, then goes onto a low (or intermediate) pressure turbine 23' through pipe 10 and finally passes into the c'ondenser,(or alower pressure turbine or engine) through pipe 9. Fig. 4 shows an arrangement similar to Figs. 2 and 3,'but fitted with a train of gearing. The driving pinions 4 on the main shaft move the'driven wheels 5 on an intermediate shaft 11 while the inion 13 on the intermediate shaft moves tie wheel 12 mounted on the propeller shaft or the like. Fig. 5 represents the ease in which more than two turbines are fixed to a common main shaft. The steam' first enters two high pressure turbines 1 and 2, then goes on to low (or intermediate) pressure turbines 1" and 2" through pipes 1.0.and finally passes into.,condensers (or lower pressure turbines or engines) through pipes 9.. The Figs. 2

to 5' show only ,a few examples of the application of -m invention to turbine ar rangement, an I hardl two or more sets bf -tur ines may be made to gear with one and same driven Wheel in accordance with my invention, as shown in the above examples, or it maybe applied to other arrangements, and the two turbines on the same main shaft may be either simple or compound, main or cruising, ahead or 4 astern, turbines.

Having thus described my invention, what I claim and desire to secure by'Letters-Patent is r 1. In a speed reducing gearing arrangement for steam turbines running at high speeds, the combination comprising a pair need to say that of turbines developing substantially constant tor ues and running at the samespced, a. shat common to said turbines, a .driven shaft, a driving pinion mounted on the common shaft intermediate of the turbines and a gear wheel fixed to said driven'shaft and arranged to mesh with said pinion.

2'. In a speed reducing gearing arrangement for steam turbines the combination comprising a plurality of turbines adapted to rotate at equal speeds and arranged with.

their shafts axially in 'line, a pinion disposed between said turbines and arrangedto rotate about the same axis as said shafts, a

driven wheel in mesh with said pinion, and clutches adapted to connect said pinion with said shafts. I

3. In a speed reducing gearing arrange of equal power and adapted to-rotate at equal speeds, a common shaft for saidturbines a pinion comparatively long as compared with its diameter fixed on the common shaft half Way between. the turbines, and a driven Wheel arranged in mesh with said pinion. I

'YEITARO OGAWA.

Witnesses: 1

.YASHIKA IKEDA',

TOMOJIRO KITAJIMA.

'ment for steam turbines, a pair of turbines 

